This invention relates to a transparent flat body including two transparent cover layers (1, 2) that confine between them an active layer (3) whose transparency varies in an electric field and disposed between two electrode layers (6, 7) optionally subdivided into sections, and a photovoltaic element that is connected to two electrode layers (6, 8), preferably via a control stage (11), and that includes a photoactive layer (4) between the two electrode layers (6, 8) of the photovoltaic element (5), characterized in that the photoactive layer (4) is made of two transparent molecular components in a manner known per se, one of the two electrode layers (6, 7) of the active layer (3) is simultaneously one of the two electrode layers (6, 8) of the photovoltaic element (5), and the two transparent cover layers (1, 2) confine between them both the photovoltaic element (5) and the active layer (3).